To reduce the workload, use a command line utility to filter the log file before you read it in KiXtart.

Get hold of a Windows native version of "grep". This is a powerful pattern matching utility, and you can construct queries like:
code:
grep "www.bannedsite.url|anotherbannedsite.com|yetanotherbannedsite.com" PROXYLOG.TXT > FILTEREDLOG.TXT
I use "grep" a lot for extracting information from my proxy log files, looking for banned sites and suspect words. It is also useful for removing unwanted hits. For example, suppose I wanted to look for all occurences of the words "sex", "porn" and "xxx", but I was not interested in URLs which have the UK counties Sussex and Essex in them:
code:
grep -i "sex|porn|xxx" PROXYLOG.TXT | grep -i -v "essex|sussex" > FILTEREDLOG.TXT
The "-i" makes the search case insensitive, the "-v" means "lines which don't match"

There are many places to get hold of grep compiled for Windows - here is one site which has this and many other *nix tools:
GnuWin32